Originally Posted by krazykanuck

I can't say for sure because I have no experience with rental car drop off and the shuttle back to the terminal at IAH, but as a Houston resident, 1 hr at that time of day would be too tight for comfort.

Traffic usually isn't bad on 59 once you get through Downtown, but the problem is Rice is before the downtown core so you'd get stuck in that traffic until you get through downtown. If you finished an hour earlier I'd say you'd likely be fine.

What airline you flying?

Just for fun I plugged this into google maps and it says Rice to IAH is 33 minutes, at 7 pm, so 1-2 hrs after peak rush hour.

For next Tuesday, leaving around your time it says this. I would highly recommend you leave earlier, or try to take a later flight. I think the odds are against you, and I want you to not miss your flight.